超高压线路工频电场超限值对策的研究

Research on the Countermeasure for the Over Limitation of the Power Frequency Electric Field Caused by Extra-high Voltage Transmission Line

针对日益增多的超高压线路引起的环境问题,研究了超高压线路工频电场超限值对策。通过对现有的和采用屏蔽措施后的地面电场强度分布、屋顶场强分布分别进行仿真计算分析和模拟试验,确定出架设屏蔽线和接地围栏两种屏蔽方案;根据屏蔽方案在现场采取屏蔽措施,在500kV线路下边相外架设1根屏蔽线,高度11m,水平距离距边相2m,试验结果表明屏蔽后场场强降低了35%。

With the development of the social economy, the electric grid expands quickly, 500 kV transmission lines spread nearly to the whole area where people live. Environmental problems caused by extra-high voltage transmission line arise more and more. As a result, to resolve the problem of this kind, the electric power departments make many researches on this problem. Some people near the 500 kV transmission line complain that the power frequency electric field has undesirable effect on their normal life, in order to reduce the electric intensity, this paper make a research on the countermeasure＇of the over limitation of the power frequency electric field caused by extra-high voltage transmission line. The method to calculate power frequency electric field caused by transmission line is the equivalent charge method. It has two parts to accomplish it： 1） the charge on the unit length. 2） the electric field caused by the charge. From the fundamental of the image method, it is found that the value of electric intensity has relationship with some factors as follows： the voltage on the conductor, the size of the conductor, the geometric position of each conductor and the sequence of each phase. Some method to reduce the intensity of the electric field as follows： 1） heighten the conductor. 2） reduce the distance between each conductor. 3） reduce the diameter of each subconductor. 4） change the sequence of each phase. 5） to erect shield line. 6） use different voltage transmission line on one tower. The transmission line is operating, and the most possibility method is to erect the shield line. One shield line is built on below the transmission line, the height is 11m and the horizontal distance to the transmission line is 2m. The measurement result shows that the maximum value of the electric intensity is reduced at the percent of 35%. At the same time, erecting the shield line on the roof of the room can reduce the electric field intensity either.